Lichen planus (LIE-kun PLAY-nus) is an inflammatory condition that can affect your skin and mucous membranes.

On the skin, lichen planus usually appears as purplish, often itchy, flat-topped bumps. In your mouth, vagina and other areas covered by a mucous membrane, lichen planus forms lacy white patches, sometimes with painful sores.

Lichen planus occurs when your immune system mistakenly attacks cells of the skin or mucous membranes. The reason for this abnormal immune response is unknown. You can't catch lichen planus or give it to another person. Most people can manage typical, mild cases of lichen planus at home, without prescribed medical treatment. If the condition causes pain or significant itching, you may need medication to suppress your immune system.

The symptoms of lichen planus vary depending on the areas affected. Typical signs and symptoms include:

Purplish, flat-topped bumps, most often on the inner forearm, wrist or ankle, but sometimes on the external genitals

Itching

Blisters that may break to form scabs or crusts

White spots or patches in the mouth — inside the cheeks or on the gums, lips or tongue

Painful oral or vaginal ulcers

Hair loss and scalp discoloration

Nail damage or loss

When to see a doctor

If tiny bumps or a rash-like condition appears on your skin for no apparent reason, such as a known allergic reaction or contact with poison ivy, see your doctor. Also, see your doctor if you experience any signs or symptoms associated with lichen planus of the mouth, genitals, scalp or nails. Because a number of skin and mucosal conditions can cause lesions and discomfort, it's best to get a prompt and accurate diagnosis.

The cause of lichen planus is unknown, though strong evidence suggests that inflammation, controlled by the immune system, gives rise to the lesions. However, certain diseases, medical conditions or other factors may act as triggers of lichen planus in some people.

Certain medications for heart disease, high blood pressure or arthritis

Anyone can develop lichen planus, but the condition most often affects middle-aged adults.

Lichen planus can be difficult to manage on the vulva and in the vagina, causing severe pain and sometimes leaving scars. Sexual dysfunction can become a long-term complication.

There is some evidence that lichen planus may increase your risk of a skin cancer known as squamous cell carcinoma, though the risk is small. Your doctor may recommend routine screening for evidence of cancerous cells in tissues affected by lichen planus.

You'll likely start by seeing your family doctor or a general practitioner. You may be referred to a specialist in skin diseases (dermatologist). To get the most out of your consultation, be prepared to provide the following information:

The name and contact number of any physician you have seen recently or see regularly

Prescription medications and dosages

Over-the-counter drugs or dietary supplements you take regularly

What to expect from your doctor

Your doctor will likely ask you these questions:

When did the bumps or other lesions appear?

Where on your body have you found the lesions?

Are the affected areas itchy, painful or uncomfortable?

How would you describe the severity of the pain or discomfort — mild, moderate or severe?

Have you recently started new medications?

Have you recently had immunizations?

Do you take supplements or vitamins, or other nonprescription herbs or medicines?

Do you have any allergies?

Your doctor or dermatologist will perform a physical examination to diagnose lichen planus. To confirm the diagnosis, you may need these tests:

Biopsy. During a punch biopsy test, your doctor removes a small section of your skin, which is then examined under a microscope for cell patterns characteristic of lichen planus. You'll receive local anesthetic to numb the site and likely require stitches to close the wound.

Hepatitis C test. A nurse or assistant may draw a small sample of blood for a lab test to determine if you have hepatitis C, a possible trigger for lichen planus.

Allergy tests. Your doctor may refer you to an allergy specialist (allergist) to determine whether substances you regularly have contact with may be causing you to have allergic reactions that act as triggers for your condition.

On regular skin, lichen planus may last from a few months to several years and spontaneously clear on its own. If it affects your mucous membranes, the disease may be more resistant to treatment and prone to recur. Medications and other treatments help relieve itching and promote healing.

Corticosteroids

Corticosteroids may reduce inflammation associated with lichen planus. The side effects of corticosteroids vary depending on how you take them — as ointment applied to the skin, as a pill or as an injection. Corticosteroids are considered safe when taken as directed and for short-term use. Common side effects of topical corticosteroids may include skin problems, such as burning, reddening or thinning of the skin at the application site. When taken orally or as an injection, side effects may include high blood pressure, elevation of blood glucose and osteoporosis.

Retinoids

Retinoids are synthetic versions of vitamin A that can be applied topically or taken orally for treatment. Retinoids may be an effective treatment, but they can cause bothersome skin irritations, such as severe dryness, redness and peeling. Oral retinoids can harm unborn babies, so these medications are not recommended for women who are pregnant or may become pregnant. If you're pregnant or nursing, your doctor may advise you to delay topical retinoid therapy or choose an alternative treatment.

Antihistamines

Antihistamines act against a protein called histamine that is involved in inflammation. An oral or topical antihistamine may relieve itching or pain associated with lichen planus.

Phototherapy

Light therapy, or phototherapy, may help clear up lichen planus affecting the skin. The most common phototherapy for lichen planus uses ultraviolet B (UVB) light, which penetrates only the upper layer of skin (epidermis). There is some risk of "sunburn" with this treatment. Phototherapy using ultraviolet A (UVA) light in combination with the medication psoralen also may be effective, though it carries a small long-term risk of skin cancer and cataracts.

Addressing triggers

If your doctor suspects that lichen planus may be related to hepatitis C infection, an allergen or a drug you take, he or she will recommend steps to address the trigger, such as trying a different medication and avoiding offending allergens. You may be referred for further treatment to an allergist or, in the case of a hepatitis C infection, to a specialist in liver disease (hepatologist).

Self-care measures can help reduce the itching and inflammation caused by lichen planus. These include:

Lichen planus of the skin

A number of alternative medicines are promoted as effective treatments for lichen planus of the skin. The claims about these treatments haven't been substantiated by research. Because lichen planus goes away on its own in most people, it's difficult to judge the effectiveness of a treatment without carefully designed clinical trials.

Purported alternative treatments for lichen planus of the skin include:

Aloe vera gel

Lavender oil

Tea tree oil

Sulphur mineral baths

Vitamin supplements

A diet rich in fruit and vegetables

Oral and topical herbal medications

Cod liver oil supplements, a source of vitamins A and D

Talk to your doctor before trying an alternative treatment for lichen planus of the skin. Some alternative medicines or vitamin supplements result in serious adverse reactions when combined with prescription medicines.

Other forms of lichen planus

A couple of small clinical trials have suggested the benefit of aloe vera gel for treating lichen planus of the mouth and vulva.

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